Sedation

Pediatric physiatrists and neurologists performing pediatric electrodiagnostic evaluations have noted that extreme behavioral distress most frequently occurs among 2-6-year-olds (28,29).

While some electromyographers never utilize sedation, there has been more interest in the use of analgesia, conscious and deep sedation, and, more recently, general anesthesia with propofol or inhala- tional anesthetics. Traditional sedative choices include chloral hydrate (50-100 mg per kg), “DPT” (meperi­dine hydrochloride, phenylephrine hydrochloride, and chlorpromazine), and midazolam hydrochloride nasal spray. EMLA cream (lidocaine 2.5% and prilo- caine 2.5%) has been used during electromyographic evaluations as a topical anesthetic (30). Mean duration of topical application in infants or older children was 45-145 minutes. Greater pain relief was obtained with use of EMLA over the extensor forearm than the the­nar eminence.

While general anesthesia is usually not neces­sary, the author has increasingly involved critical care and anesthesia colleagues who have utilized either propofol (2,6-diisopropylphenol), an intra­venous sedative-hypnotic agent or inhalational anesthetics with laryngeal mask anesthesia (LMA) airways for the electrodiagnostic evaluation of 18-month-old to 6-year-old children who exhibit sub­stantial behavioral distress during an initial attempt at an electrodiagnostic evaluation without sedation.

The cost of anesthesia must be weighed against the importance of the acquisition of a thorough, tech­nically precise, and accurate electrodiagnostic eval­uation. An EMG obtained under anesthesia usually provides a suboptimal evaluation of motor unit config­uration, recruitment pattern, and interference pattern, with maximal effort but better evaluation of quiet muscle for spontaneous activity and a more compre­hensive acquisition of nerve conduction studies and repetitive nerve stimulation studies.

The key to successful data acquisition in most pediatric electrodiagnostic evaluations remains a well-organized, well-planned approach with dis­tinct diagnostic questions prospectively consid­ered. If the examination is planned to answer a specific question, it is usually possible to proceed expeditiously, completing the examination within a reasonable time (30 minutes). As children approach 6 years of age, it becomes easier to talk them through an evaluation and elicit their participation and cooperation.

Nerve conduction studies are usually better toler­ated than needle electromyography, and many pediat­ric electromyographers perform the nerve conduction studies first. Increased behavioral distress subsequent to a needle examination makes the motor nerve con­ductions, and particularly the sensory nerve conduc­tion studies, technically difficult due to excessive EMG background noise.